mm/damon/tests/core-kunit: avoid damos_test_commit stack warning

The newly added damos_test_commit() constructs multiple large structures
on the stack, which exceeds the warning limit in some cases:

In file included from mm/damon/core.c:2941:
mm/damon/tests/core-kunit.h: In function 'damos_test_commit':
mm/damon/tests/core-kunit.h:965:1: error: the frame size of 1520 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]

Split this function up into two separate ones that are called
sequentially, so they can occupy the same stack slots.

Link: https://lkml.kernel.org/r/20251204100403.1034980-1-arnd@kernel.org
Fixes: 299a88f ("mm/damon/tests/core-kunit: add damos_commit() test")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Quanmin Yan <yanquanmin1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: arndb

mm/damon/tests/core-kunit.h

@@ -924,7 +924,7 @@ static void damos_test_commit_for(struct kunit *test, struct damos *dst,
 	}
 }
 
-static void damos_test_commit(struct kunit *test)
+static void damos_test_commit_pageout(struct kunit *test)
 {
 	damos_test_commit_for(test,
 			&(struct damos){
@@ -945,6 +945,10 @@ static void damos_test_commit(struct kunit *test)
 					DAMOS_WMARK_FREE_MEM_RATE,
 					800, 50, 30},
 			});
+}
+
+static void damos_test_commit_migrate_hot(struct kunit *test)
+{
 	damos_test_commit_for(test,
 			&(struct damos){
 				.pattern = (struct damos_access_pattern){
@@ -1230,7 +1234,8 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damos_test_commit_quota),
 	KUNIT_CASE(damos_test_commit_dests),
 	KUNIT_CASE(damos_test_commit_filter),
-	KUNIT_CASE(damos_test_commit),
+	KUNIT_CASE(damos_test_commit_pageout),
+	KUNIT_CASE(damos_test_commit_migrate_hot),
 	KUNIT_CASE(damon_test_commit_target_regions),
 	KUNIT_CASE(damos_test_filter_out),
 	KUNIT_CASE(damon_test_feed_loop_next_input),